title: Halogen and chalcogen cation pools stabilized by DMSO. Versatile reagents for alkene difunctionalization.
abstract: Halogen and chalcogen cations (X(+) = Br(+), I(+), ArS(+), and ArSe(+)) were generated by low-temperature electrochemical oxidation in the presence of dimethyl sulfoxide (DMSO) and were accumulated in the solution. DFT calculations indicated that DMSO stabilizes these cations by coordination. The complexes of I(+) with one and two DMSO molecules were observed by cold-spray-ionization MS analyses. The stability of the resulting cation pools of X(+) increased in the order of Br(+) < I(+) < ArS(+) < ArSe(+), which could be explained in terms of the electronegativity of X. The cation pools served as versatile reagents for organic synthesis; the reactions with alkenes gave β-X-substituted alkoxysulfonium ions, which were converted to the corresponding carbonyl compounds by the treatment with triethylamine, whereas the treatment with methanol gave the corresponding alcohols. The reactions with aminoalkenes and 1,6-dienes gave the cyclized products.
authors.affiliation: Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University , Kyotodaigaku-Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Ashikari
authors.forename: Akihiro
authors.initials: A
authors.lastname: Shimizu
authors.forename: Toshiki
authors.initials: T
authors.lastname: Nokami
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Yoshida
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D002412:Cations / Q000737:chemistry*; D018011:Chalcogens / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004121:Dimethyl Sulfoxide / Q000737:chemistry*; D004563:Electrochemistry; D006219:Halogens / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000475:Alkenes; D002412:Cations; D018011:Chalcogens; D006219:Halogens; D004121:Dimethyl Sulfoxide